This invention relates to a straightening machine for straightening sheets and flat materials which has a lower and an upper roller frame, each having mounting bars spaced a predetermined distance apart for holding positively driven upper or, respectively, lower straightening rollers. The upper and lower straightening rollers are staggered with respect to one another so that the rollers of the upper frame are in alignment with the spaces between the rollers of the lower frame.
Each straightening roller of the upper and lower frame has its own separate drive shaft through which it is driven from a transmission which is fixed, together with the respective roller frame, to a bed plate or the like. Four stay bolts secured by a lock nut and screwed into the lower roller frame are also normally provided to ensure correct alignment of the upper to the lower roller frame, and, in particular, to prevent parallel relative displacement between the rollers of the upper frame and those of the lower frame. Mounted on each of these stay bolts is a compression spring so that the upper roller frame is cushioned on the lower frame. The upper frame can be moved towards or away from the lower frame, for example, by turning a nut acting on the stay bolt.
In these known straightening machines, the upper roller frame can only be raised very slightly away from the lower frame, particularly because of the arrangement of the driving mechanism. As a result, the straightening rollers are relatively inaccessible and cleaning of the straightening apparatus is very difficult and time consuming. The arrangement of the driving mechanism prevents the upper roller frame from being tilted upwards because this would cause the individual drive shafts of the straightening rollers to be twisted over one another. Moreover, the compression springs on the stay bolts would have to be placed back into position after each frame opening because they would fall off whenever the frame was opened.
Accordingly, an object of the present invention is the provision of a straightening machine roller assembly in which the straightening rollers of an upper and lower roller frame, which cooperate with each other during the straightening process, can easily be moved far enough apart to allow for much easier cleaning of the machine and/or simple replacement of individual parts, for example, individual straightening rollers. More particularly, a straightening machine constructed according to the teachings of the present invention is distinguished from known roller straightners by the fact that the upper roller frame can be tilted about an axis by a large angle away from the lower roller frame, for example, an angle greater than 90.degree..
According to one advantageous embodiment of the invention, two separate transmissions, one associated with the upper roller frame and one associated with the lower roller frame, are employed. The transmissions are drivingly connected by a connecting shaft having an axis which lies in the pivotal axis between the lower and the upper roller frame. This connecting shaft is preferably a universal joint shaft so that the upper roller frame can be slightly shifted away from the lower frame to adapt the space between them to the thickness of the material, the straightening pressure, etc. without the need for separate drives for the upper and the lower roller frame.
To prevent the compression springs, which provide the flexible pressure of the upper roller frame against the lower frame, from falling off the straightening machine as mentioned above, they are not mounted on the stay bolts, but rather are moved slightly away from them and constructed, for example, as separate spring bolts.
The above objects and construction details of the invention are more fully described below with particular reference being had to the drawings, which illustrate by way of example one embodiment of the present invention.